Michael hubipfner



- (No Model.)

M. HUMPFNER.

DEVICE FOR SHARPENING SGYTHES.

No. 375,708. Patented Dec. 27, 1887.

Fig.2.

N. PETERS. Phololilbflgrapher, wnhington. DJ:

UNITED STATES PATENT OFFICE MICHAEL HUMPFNER, OF FRANKFORT-ON-THEMA IN, GERMANY.

DEVICE FOR SHARPENING SCYTHES.

SPECIFICATION forming part of Letters Patent No. 375,708, dated December 27, 1887.

Application filed July 26, 1887. Serial No. 245,391. No model.) Patented in Luxemburg April 5, 1837, No. 830, and in Belgium April 15, 1587, No. 76,959, and May 16, 1887, No.77,252.

To aZZ whom it may concern.-

Be it known that 1, MICHAEL Hl'lMPFNER, a subject of the Emperor of Germany, residing at Frankfort-on-the-Main, Germany, have invented certain new and useful Improvements in Apparatus for Sharpening Scythes, (for which I have obtained Letters Patent of the following countries, to wit: Belgium, April 15, 1887, No. 76,959, and May 16, 1887, No. 77,252, and Lnxemburg, April 5, 1887, No. 830,) of which the following is a specification.

The present mechanical way of sharpening scythes with a hammer is always attended more or less with distortion or warping of the scythe, in consequence of the equable effect of blows on the metal of the scythe, which presents differences in hardness and thickness. To guard against this the present apparatus has been constructed. It permits, on the one hand, the gradual extension of the path of the hammer and on the other a corresponding decrease in the force of the blows, which at first is very great,su ch as beforewas not possible except by hand and in three or four times the time. Furthermore, instead of the previous level form of the anvil, an arched one has been constructed, in order that the scythe may not rest on it, but glide over it;and, finally, the appli cation of the apparatus has been rendered independent of place-that is, practicable both at home and in the field, by small volume and weight as well as by the employment of a knee board, as explained farther on.

In the accompanying drawings, Figure 1 is a perspective view of the sharpening apparatus, and Figs. 2 and 3 detail views of parts of the same.

Ais thesharpening-hammer, whichis moved up and down in a slit, a, of the stand B by means of its guiding-piece A. This guidingpiece A, which in Fig. 3 is represented in detail, serves at the same time to lift the hammer connected with it by means of a projection, A at its upper end and the three-cornered thumbdisk C, Fig. 2. Therenpon the hammer is driven down by the spiral springD as soon as the projection A leaves one of the eccentric bends of the thumb'disk. In consequence of this direct lifting of the hammer A, the spring D may be comparatively very strong, and yet the blows caused by it may be deadened at will by loosening the spring by means of thescrew-muff M. The guiding-bow F, which is almost parallel to the anvil E, al-

lows itself to be turned at one end, T, ina fixed 7 point, while the end S, turned to the workman, may be given different positions in the slit y by means of the clamp or setting screw 0.

With the object of regulating the motion of theend Sof the bow, for-the purpose of gradu- 6 ally passing the scythe through in the operation of sharpening, a scale has been fixed at the edge of anvil E, corresponding with the slit 3 The anvil E, with the hardened-steel boltG, which has an arched head and is movably fixed in the anvil, together with the overarching guiding-bow, F, forms what is called a gniding mouth. The steel bolt G is coneshaped, and may easily be knocked out from below when worn out.

hen the end S of the guiding-bow F is set on the first mark of the slit y in the beginning of the operation, the scythe, set in the guiding-mouth, is struck on a breadth of about three millimeters by the hammer, which in this instance acts with full force. After accomplishing this first path, the end S of the guidingbow is moved forward by about one millimeter by means of the setting-screw 0, so that the hammer now strikes only the part of the path it has already traversed, extending it farther, which is continued by means of farther setting forward of the end of the bow until the whole path of the hammer has been passed over. As the 85 metal grows thinner, the hammer must not strike it with the same force, and for this purpose this striking-spring E hasto be gradually loosened. This is accomplished by the screwmuff M, mentioned above, which on its out- 1 side has a screw-thread moving in the projection :0 of the stand B. Within the screw-muff has a smooth bore of corresponding length, in which the hammer-pin carrying the spring glides up and down.

By means of the lateral setting of the guiding-bow F, movable at its other end around a fixed point on gradual displacement of the hammers path, the scythe is brought into ob- 'lique position to the tail-piece of the hammer. 10c,

This, in connection with the arched shape of the head of the anvil, allows the scythe to be so struck that no warping or notching can occur even though the metal be extremely thin. Finally, the combination of the overarching guiding-bow, which may be turned laterally, with the arched head of the anvil obliges the clumsiest and laziest Workman to hold the scythe in right position, because the arched head of the anvil allows only one point to rest, and the guiding-bow, set at the correct angle, renders too great an inclination of the scythe impossible.

The apparatus is mounted in oblique position on one end of a board about fifty centimeters long for the purpose ofrendering possible work in the open field, which is done by holding the board fixed on the ground by means of the right knee,while the right hand turns the crank and the left hand draws the scythe through. In this manner my apparatus secures safe sharpening even on the loosest sandy soil and on wet meadows. The board, moreover, may

be furnished with two carrying-straps, so that the whole apparatus can be comfortably carried on the back. I

WVhat I claim as new isv 1. In an apparatus for sharpening scythcs, the combination, with the hammer A, frame B, in which said hammer is mounted, and means for reciprocating the same, of a guiding-bow, F, pivoted at one end, and an anvil, E, having an arched head, G, substantially as described.

2. In an apparatus for sharpening scythes, the combination, with a trip-hammer and an anvil, of the bow F, pivoted at T to the anvil, and the set-screw O, secured to the other end of said bow, substantially as described.

In testimony whereof I have aflix'ed my sig- 1,0 nature in the presence of two Witnesses.

MICHAEL HUMPFNER.

Witnesses:

G. MILEZ nwsKI, L. MASOHMANN. 

